One of the "deepest" and most destructive audio problems is clipped audio where the audio hits up against the 0dB digital limit. The result is distorted or "buzzing" audio that is horribly unpleasant. Here's how you can potentially re-construct clipped audio.

This plugin recreates clipped audio by using an algorithm which estimates how the waveform would be shaped had it not been limited by the digital recording system and the gain settings used. 

Settings:

• Threshold — Tells the plugin where you want it to work to re-construct clipped portions of the waveform. Generally, this should be set just below the actual level of clipping. All of the bits you want it to fix should cross the threshold and all the bits you do NOT want it to change should NOT touch the threshold. You can also unlink the upper and lower thresholds if you only have clipping on one side
• Suggest — RX does its best to set the threshold for you
• Quality — tradeoff. Low quality may not produce results which are as good, but it processes much more quickly. Inverse for High. Compromise for Medium
• Make-up gain — use this to reduce the gain after the peaks have been repaired so that you it does not clip again
• Post-limiter applies a limiter after the peaks are repaired so that the do not clip again. Note that if you are working with a file saved in 32-bit float format, this module can repair the clips and store them above 0dBFS. However, when you play that back, it will clip. So you’ll still need to attenuate or limiter the audio